Since the late 1940's, there has been an increased activity with regard to providing means and methods to clean contaminants from water, especially lakes, ground water, streams and ponds. In addition to the need to clean rivers and streams, there is a great need for having the capability for cleaning waste ponds that are used for detritus from chemical or electrical processes, for example, the removal of radium from quench ponds and the removal of mercury and other metals from conditioned water from manufacturing sites.
A major problem associated with such “cleaning” methods is the ultimate cost. That is why many methods have evolved that use complexing agents and the like rather than fillers as filtration media, as some of these complexing agents are capable of being reversed, that is, after the metal, for example, is sequestered, the process can be reversed to collect the sequestered metal and either reuse it or concentrate it to provide a proper disposal means for it.
Campbell, et al in U.S. Pat. No. 6,803,106 describes a modern material that is used for purification of waste chemical and metal process streams and for the separation and identification of proteins, peptides, and oligionucleotides. This material is a multi-layered macromolecule wherein the layers are covalently bonded together and wherein the macromolecules are covalently bonded to solid particulate substrates.
There is also a system for extracting soluble heavy metals from liquid solutions that is embodied in two patents that issued to Rosenberg and Rosenberg and Pang, respectively. The first is U.S. Pat. No. 5,695,882 that issued Dec. 9, 1997 and the second is U.S. Pat. No. 5,997,748 that issued on Dec. 7, 1999. Both of these patents deal with a process for removing ions of dissolved heavy metals and complex heavy metals from various solutions using an activated surface that is the reaction product of a polyamine with a covalently anchored trifunctional hydrocarbylsilyl that yields non-crosslinked amino groups to which functional chelator groups can be covalently attached.
It is important to note that these materials are non-crosslinked as is expressly set forth by the patentees therein.